Electroplating method and apparatus



Nov. 20, 1962 F. o. HOUGH ETAL 3,065,153

ELECTROPLATING METHOD AND APPARATUS Filed oct. 15, 195s s sheets-sheet 1 Nov. 20, 1962 F. o. HouGH ETAL ELECTROPLATING METHOD AND APPARATUS 5 Sheets-Sheet 2 Filed OCL. l5, 1958 NOV- 20, 1962 F. o. HOUGH ETAL 3,065,153

ELECTROPLATING METHOD AND APPARATUS Filed OCT.. l5, 1958 3 Sheets-Sheet 5 5,7 1N VENTRS tates ifiatent @than iel Patented Nov.` 20, i952 3,665,153 ELECTRPLATEJG lvllll AND APPARATUS Fred i). Hough and Donald R. Scott, indianapolis, 1nd assignors to General Motors Corporation, Detroit, Mien., .a corporation of Delaware Filed Oct. 15, 1958, Ser. No. 767,325 16 Claims. (Cl. 20d-26) This invention relates to the manufacture of bearings and more particularly to a method and apparatus for electrodepositing bearing layers onto the surfaces of steel backed bearings.

l-lrgh quality bearings, such as those which are used on the crankshafts of large reciprocating engines, are made by applying a single layer or plurality of layers of a suitable bearing metal onto a supporting member of a stronger metal. It is frequently preferable to apply the bearing metal by electrodeposition in which the stronger and harder supporting metal functions as a cathode. Various methods and apparatus have been proposed for electrodepositing low friction metals, such as silver, onto steel bearing shells. However, these previously proposed methods and apparatus either produced unsatisfactory results or were unduly time consuming and costly.

ln making bearings, for example, it is desirable to electrodeposit a relatively soft bearing metal, such as silver, at a fairly rapid rate which requires fairly high current densities. It is also desirable to use insoluble electrodes in plating relatively soft metals, such as silver, thereby requiring the use of extremely high amounts cagitation.

By means of the present invention bearing shells can be more economically and more rapidly produced in a manner which permits uniformity of the product under production conditions. Our invention permits the application of thick, more uniformly distributed, dense deposits on a bearing shell. Moreover, the application of these layers is more rapidly accomplished by simultaneously electrodepositing coatings on both the interior and exterior of the bearing Shell. Thus, separate machining, grinding and annealing steps conventionally ernployed in the previous methods are eliminated by our invention. Moreover, the quality of the plate and the rate of electrodeposition can be accurately controlled under commercial production conditions using our invention.

A primary object of our invention is to provide an improved method and apparatus for making steel backed bearings which have thicker, denser and more uniform simultaneously formed bearing layers than that heretofore obtained. This invention further provides a method and apparatus for more rapidly and more uniformly obtaining superior Steel backed bearings than that obtained in any commercially practiced processes heretofore known.

Briefly, the invention comprehends a method and apparatus in which a lbearing shell is vertically disposed between conforming anodes which are spaced from adjacent surfaces of the bearing shell so as to provide annular cylindrical chambers therebetween. An electroplating solution is continuously moved over the surfaces of the plating shell through the chambers. A positive potential is induced in each of the anodes in such a manner that the potential on each of the anodes can be separately regulated. A negative potential is induced on the bearing shell. The bearing shell and anodes are mounted on a suitable support through which the electroplating solution is introduced into the chambers adjacent the bearing shell` Means are provided to simultaneously direct the plating solution into the inner and outer lchambers of the bearing shell in which the relative flow of electroplating solution into the inner and outer chambers is regulated.

tuer objects, teatures and advantages or the present invention will become more apparent trom tue renowing description of preferred embodiments thereof and from the drawings, in which:

FlUURE 1 is an elevational View in partial section showing .an electroplating apparatus such `as contemplated by the present invention;

FlGURE 2 is an enlarged sectional View of the bearing shell and lanode assembly shown in lilGUliE l;

Ft'GURE 3 is a sectional View along the lines 3-3 of PGURE 2;

FIGURE 4 is a sectional view along the lines 4 4 of FiGURE 2;

MGURE 5 is an enlarged sectional View showing a second embodiment of the bearing shell and anode assembly such as contemplated for use in the present invention; and

FlGURE 6 is a sectional view along the lines 6-6 of lFlGURE 5.

"the general view of the apparatus shown in FGURE l includes an electroplating tank lll containing an electrolyte solution 12. The tank, of course, is made of a material or has a lining (not shown) which is nonreactive with the particular electroplating solution being used. Materials, such as iron, steel, plastic, etc., can be used to make a tank for silver plating. Depending into the electroplating tank are frame members 14 and 1d on which are supported a motor 18 and a pump l U-shaped directing tube 2?, attached to the pump 29 conveys electroplating solution from the pump to a bearing shell 24 Which is to be plated. At the end of the tube EZ Opposite the pump 2li the tube has a plate member 26, secured by welding or the like, to form a flange. A spray head adaptor 2d is secured to the plate member by the bolts Sil and 32.

A spray head 34 is fitted over the spray head adaptor 2li .and an annular, cylindrical, insoluble anode 36 is, in turn, supported on the spray head. Tue bearing shell 24 is disposed within the outer anode 36 and a cylindrical, inner, insoluble anode 3-3 is positioned v'fthin the bearing shell. The bearing shell 24 and anodes and 33 :are suitably connected to a source of current 4G to induce negative and positive potentials, respectively,

therein. The anodes each have variable resistance means i2 interjacent the source of current dit to provide means for independently varying the current density on the inner and outer surfaces of the bearing shell during electrodeposltion.

The electroplating solution 12 in the plating tank lil enters the pump 2li through the ports dfi. The pump rnoves the solution through the directing tube 22 up through the spray head adaptor 2S and spray head 3e upwardly over the bearing shell. The solution l?, overflows Ifrom the bearing shell anode assembly back into the plating tank 1d Where it again enters the pump Z@ for recirculation.

Referring now to FIGURES 2, 3 and 4, the cylindrical spray head adaptor 23 has a conical passage 46 extend therethrough which has its greatest diameter at the upper surface 43 of the adaptor. The spray head 3d, which is positioned on the adaptor Z, is cylindrical member having an annular projection 5l) on its 1ct/ver surface 52. The projection circumferentially engages the outer periphery 54 of the adaptor 2S so as to inhibit transverse movement therebetween. The annular, cylindrical, insoluble anode 36 havingr a counterbore in its lower end forming a shoulder 5d is positioned around the upper end of the spray head 34. The upper end of the spray head is of reduced diameter forming a shoulder 58 on its outer periphery. The outer anode 36 is supported on the spray head 34 by abutment of the shoulders 56 and 58 with surfaces on the spray head and anode, respectively.

The bearing shell and inner anode form a composite assembly 60 which is fitted in a recess 62 in the upper surface 64 of the spray head 3ft. The bearing shell 24 is positioned within the outer anode 36v and spaced therefrom to form an outer annular chamber 7d therebetween. Electrically non-conductive masking rings 6e and 613 are located at each end of the vertically disposed bearing shell 24. The bearing shell is closely fitted into annular grooves 78 in adjacent surfaces of each of the masking rings 66 and 68. Against the opposite surfaces of each of the masking rings are circular bearing shell end plates 72 and 74 having apertures 7 6 therein.

A tubular, insoluble anode 38 is concentrically disposed within the bearing shell 24 between the end plates 72 and 74. The 4anode is spaced from the bearing shell so as to form an annular chamber i8 therebetween. The anode is located within the bearing Shell by means of a central tie bolt 80 which extends through the anode end caps 82 and 84. The upper anode end cap 82 engages a nut 86 on the tile bolt to provide a positive stop limiting the upward movement of the anode. The lower end cap 84 engages the lower end plate 74 to lock the anode in position.

The upper end of the assembly is secured by means of a nut 88 in conjunction with washers 90 and 92 engaging the upper end plate. A conical member 9d below the lower bearing shell end plate '74 has a threaded opening 96 therein which engages the central tie bolt 8u to secure the entire assembly.

The spray head 34 has a conical passage 98 extending vertically through its center communicating the inner chamber 78 with the passage 45 in the adaptor 23. Additional passages 100 in the spray head 34 similarly communicate the outer chamber 71 with the passage 46 in the adaptor 28. The conical member 94 on the lower end of the inner anode 38 depends within the central passage 98 in the spray head 34. By raising and lowering the inner anode 38 the conical tip 94 on its lower end regulates the ow of solution through the central passage 98.

A positive potential is induced in the inner anode 38 by attaching an electrical terminal clip (not shown) to the upper end 102 of the tie bolt 80. The tie bolt is insulated from the bearing shell 2d by means of the electrically non-conductive bushings 184 and 166 in the end plates, the non-conductive washer 92, the non-conductive lower anode end cap 84 and the non-conductive conical member 94. Of course the spray head 34 is of a nonconductive material, as is the spray head adaptor 28.

A negative potential is induced in the bearing shell 24 by means of an insulated wire 108 extending through the end cap 72 and masking ring 66 into contact with the bearing shell 24. A positive potential is induced in the outer, insoluble anode by means of an insulated wire 110 suitably attached thereto. Electrical terminal clipsV (not shown) can be attached to the ends of the wires leading from the bearing shell and the outer anode to facilitate connection to a source of current. The handling of the composite assembly 68 is facilitated by provision of the hooks 111 on the upper bearing shell end plate 72.

Another modiiication of the apparatus contemplated by the invention is shown in FIGURES and 6. This modication of the invention diiers from that shown in FlGURES 2, 3 and 4 in that the composite bearing shell inner anode assembly 68 is of a slightly different construction. This latter modiiication permits a quick adjustment of the inner anode 38 while the apparatus is in use to regulate the ilow of electrolyte through the central passage in the spray head. In this modilication the -inner anode .38' is suspended relatively freely within the bearing shell 2d with no lower lateral stabilizing means. A split ring 112 which is adjustable by suitable bolt means 114 is in circumferential frictional engagement with the upper end of the bearing shell 24. An inner anode support member 116 secured to the split ring extends over the open upper end of the bearing shell. A tubular, insoluble anode 88 is suspended within the bearing shell 24 from the support 115. rEhe anode is spaced from ythe bearing shell to form an annular inner chamber 78 therebetween. The anode 38 is suspended from the support 116 by means of a central tie bolt Sti which passes longitudinally through the anode to its lower end where it is in engagement with the threaded opening in a conical end piece 94 on the inner anode. The upper end of the inner anode 38 has a conductive end plate 82 which has an opening through which the central tie bolt 86 passes. The inner anode assembly is secured to the tie bolt by means of a nut 86' which engages with the upper anode end piece 82.

The tie bolt 86) is, in turn, secured to the anode support member 116` by suitable nut means `118 and 121i. T he handling of the composite assembly is facilitated by means of suitable hooks 111 which are secured to the split ring 112.

A positive potential is induced on the inner anode 38 by connecting an electrical terminal clip (not shown) on the upper end of the `tie bolt 88. The bearing shell is insulated from the anode by means of the non-conductive washers 122 between the tie bolt, locking nuts 118 and 12) around the anode support member 116 and a nonconductive bushing 124 in the support member itself.

A negative potential can be induced on the bearing shell by attaching another electrical terminal clip (not shown) to the split ring 112. However, in most instances, it is preferred to inhibit unnecessary electrodeposition on the split ring. Accordingly, insulating means 126 between the split ring and the bearing shell are provided and a negative potential is induced on the bearing shell by means of an insulated wire 1128 which is held in place under the insulation by the split ring 112.

A positive potential is induced in the outer cylindrical anode 36 by means of an insulated wire 118. To facilitate connecting the wires 128 and 110 to the source of current, suitable electrical terminal clips (not shown) can be attached to the ends of the wires.

The electrically non-conductive materials which are to be used in constructing the apparatus of our invention can be of any type which is relatively inert in the electroplating solutions employed and which is suhiciently strong. Materials such as plastics, ceramics, etc., can be used. When silver plating various metal parts, such as bearing shells, for example, the various metal parts are cleaned 1n a conventional manner, as by degreasing in a suitable solvent ethylene ester or the like. If necessary the parts can also be cleaned of oxides and other surface impurities in the known and accepted manner for such cleaning, as by alkaline or acetic cleaning. Satisfactory results are obtainable when anodically cleaning the bearing shells in a dilute aqueous solution of sodium hydroxide (about 10% sodium hydroxide, by weight), under a full current from a six volt source for about one minute. Although, heretofore, each surface of the bearing shell has been separately cleaned by means of the present invention, the alkaline cleaning described above, as well as the subsequent operations, can all be simultaneously performed on the inner and outer surfaces of the bearing shell.

Subsequent to the acetic cleaning the cleaned part is thoroughly rinsed with water to remove the last traces of the cleaning solution and then cathodically etched in a solution containing four grams per liter of nickel chloride (NiClg-l-ZO) in 18 F. Baume to 20 F. Baume hydrochloric acid.

Using carbon anodes the bearing shell is cathodically etched under full current from a six volt source for about one minute. After the cathodic etch, the part is thor- Nickel (metal) 7085 grams per liter. Nickel liuoborate (Ni(BF4)2) 280-340 grams per liter. Boric acid (HSBOS) 25-35 grams per liter. pH 3.04.0.

Temperature 75 F.-1l0 F. Anodes Nickel.

The bearing shell is then rinsed thoroughly again and immersed as a cathode in a silver strike solution for about one minute under a current density of about 2O amperes per square foot to 25 amperes per square foot of cathode surface area. The following is an example of a silver strike solution which can be used:

Potassium cyanide (free) G-165 grams per liter. Silver cyanide (AgCN) 2-4 grams per liter. Anodes Stainless steel.

Directly from the silver strike solution the bearing shell silver is plated.

The electrodeposition of the silver plate can be effected substantially as disclosed in United States Patent No. 2,440,672 in the name of Harry J. Green which is also assined to the assignee of the instant invention.

When silver plating, the electroplating solution is pumped through the directing tube up to the spray head where the solution is divided into two streams moving through the passages 98 and litt) into the inner and outer chambers. While the solution is flowing through the chambers electric current is passed through the anodes and the bearing shell in such a manner as to provide optimum current density ratios. Although the current density and rates of electroplating solution ow are variable, we have found that, when silver plating, current densities or' about 30 amperes per square foot -to 50 amperes per square foot are generally satisfactory.

The particular rate of flow of the electroplating solution is also variable. When plating a steel bearing shell or a length of about 14 inches in length, 3.9 inches in diameter and a wall thickness of about 0.4 inch, a llow rate of about i8 gallons per minute and l2 gallons per minute can be used, respectively, in the outer and inner chambers.

The specific composition of the anodes is not material to this invention and any relatively insoluble conductive substance can be used. Generally, we have found lthat a low carbon steel is generally satisfactory. After a suiiicient duration of electrodeposition, the parts are removed from the plating solution, washed and dried.

Although our invention has been especially described in connection with silver plating, our invention contemplates the electrodeposition of other metals or alloys. By the term silver as used herein, we intend to encompass silver base alloys, as well, and by the term metal as used herein, we mean to include mixtures of metals or alloys.

Although our invention has been described in connection with certain specific examples thereof no limitation is intended thereby except as delined in the appended claims.

We claim:

l. The method of simultaneously electroplating the inner and outer surfaces of a tubular member, said method comprising the steps of generally concentrically disposing in spaced relationship a lirst cylindrical anode within said tubular member, generally concentrically disposing in spaced relationship a second cylindrical anode around the outer surface of said tubular member, concurrently flowing at mutually different rates a stream of electrolyte between the tubular member and each of said (i anodes, inducing a negative potential on said tubular member and while flowing said electrolyte inducing mutually different positive potentials on said rst anode and said second anode so as to electrodeposit in a predetermined thickness ratio a metal coating on each of said surfaces.

2. The method of simultaneously electrodepositing a metal on the inner and outer surfaces of a tubular member, said method comprising the steps of placing a first cylindrical anode within a tubular member and spacing said anode from the inner Wall of said tubular member so as to form an annular chamber therebetween, placing a second cylindrical anode around said tubular member and spacing said second anode from the outer wall of said tubular member so as to form a second annular chamber therebetween, passing an electrolyte at mutually different rates of ow through each of said chambers, the rate of flow through said second chamber being greater than the rate of How through said rst chamber, inducing a negative potential on said tubular member and while passing said electrolyte through said chambers inducing mutually dierent positive potentials on said iirst anode and said second anode, the potential on said second anode being greater than the potential on said first anode so as to electrodeposit in a predetermined thickness ratio a metal coating on each of said walls.

3. An apparatus for electrodepositing metal simultaneously on the inner and outer surfaces of a bearing shell comprising a support for a bearing shell, means for supporting a cylindrical anode within said bearing shell in spaced relationship so as to form an annular inner chamber therebetween, means for circumferentially surrounding said bearing shell with a second anode which is spaced therefrom so as to form an outer annular chamber therebetween, means for passing an eleotroplating solution simultaneously through said inner and outer chambers, means for regulating the relative rates of flow of said solution through said chambers, means for applying a positive potential to said anodes, and means for applying a negative potential to said bearing shell.

4. An apparatus for electrodepositing metal simultaneously on the inner and outer surfaces of a bearing shell comprising a support for a bearing shell, means for supporting a cylindrical anode within said bearing shell in spaced relationship so as to form an annular inner chamber therebetween, means for circumferentially surrounding said bearing shell with a second anode which is spaced therefrom so as to form an outer annular chamber therebetween, means for passing an electroplating solution simultaneously through said inner and outer chambers, means for regulating the relative rates of flow of said solution through said chambers, means for applying a separately variable positive potential to each of said anodes, and means for applying a negative potential to said bearing shell.

5. An apparatus for electrodepositing metal simultaneously on the inner and outer surfaces of a tubular member comprising a reservoir for containing an electroplating solution, a support for a tubular member, means for supporting a cylindrical anode within said tubular member in spaced relationship so as to form an annular inner chamber therebetween, means for circumferentially surrounding said tubular member with a second anode which is spaced therefrom so as to form an outer annular chamber therebetween, means for providing movement of a solution from said reservoir through said chambers, means for regulating the relative rates of flow of said solution through said chambers, means for applying a separately variable positive potential to each of said anodes, and means for applying a negative potential to said tubular member.

6. An apparatus for electrodepositing metal simultaneously on the inner and outer surfaces of a tubular member comprising a reservoir for containing an electroplating solution, means for supporting a tubular member with its longiutdinal axis in vertical disposition, means for supporting a cylindrical anode within said tubular member in spaced relationship so as to form an annular inner chamber therebetween, means for circumferentially surrounding said tubular member with a second anode which is spaced therefrom so as to form an outer annular chamber therebetween, means for providing movement of an electroplating solution from said reservoir upwardly through each of said chambers simultaneously, means for regulating the relative rates of ow of said electroplating solution through said chambers, means for applying a separately variable positive potential to each of said anodes, and means for applying a negative potential to said tubular member.

7. An apparatus for electrodepositing metal simultaneously on the inner and outer surfaces of a bearing shell comprising a reservoir for containing an electroplating solution, means for supporting a bearing shell, means for directing an electroplating solution from said reservoir to one end of said bearing shell, means for supporting a cylindrical anode within said bearing shell in spaced relationship so as to form an annular chamber therebetween, means for circumferentially surrounding said bearing shell with a second anode which is spaced therefrom so as to form an outer annular chamber therebetween, means providing movement of said solution from said reservoir through said chambers adjacent said bearing shell, means for regulating the relative rates of ow of said solution through said chambers, means for applying a separately Variable positive potential to each of said anodes, and means for applying a negative potential to said bearing shell.

8. An apparatus for electrodepositing metal simultaneously on the inner and outer surfaces of a bearing shell comprising a reservoir for containing an electroplating solution, means for supporting a bearing shell at its lower end with its longitudinal axis in vertical disposition, means for directing an electroplating solution from said reservoir to said support means, means for supporting a cylindrical anode within said bearing shell in spaced relationship so as to form an annular chamber therebetween, means for circumferentially surrounding said bearing shell with a second anode which is spaced therefrom so as to form an annular chamber therebetween, means providing movement of said solution from said reservoir through said chambers adjacent said bearing shell, means for regulating the relative rates of flow of said solution through said chambers, means for applying a separately variable positive potential to each of said anodes, and nkileans for appying a negative potential to said bearing s ell.

9. An apparatus for electrodepositing metal on the inner and outer surfaces of a bearing shell comprising a reservoir for containing an electroplating solution, means for supporting a bearing shell, means for directing an electroplating solution from said reservoir to said support means, means for supporting a cylindrical anode within said bearing shell in spaced relationship so as to form an annular chamber therebetween, means for circumferentially surrounding said bearing shell with a seco-nd anode which is spaced therefrom so as to form an outer annular chamber therebetween, means in said support for communicating said chambers with said directing means, means for providing movement of said solution from said reservoir simultaneously through said inner and outer chambers, means on said inner anode for coaction with said support so as to regulate the rates of flow of said solution through said chambers, means for applying a separately variable positive potential to each of said anodes, and means for applying a negative potential to said bearing shell.

10. An apparatus for electrodepositing metal simultaneously on the inner and outer surfaces of a tubular member comprising a reservoir for containing an electroplating solution, means ,for supporting a tubular member,

means for directing an electroplating solution from said reservoir to said support means, means for supporting a cylindrical anode within said tubular member in spaced relationship so as to form an annular chamber therebetween, means for circumferentially surrounding said tubular member with a second anode which is spaced there from so as to form an outer annular chamber therebetween, means in said support for communicating said chambers with said directing means, means for providing movement of said solution from said reservoir simultaneously through said inner and outer chambers, means on said inner anode for coaction with said support so as to regulate the rates of ow of solution through said chambers, means for applying a separately variable positive potential to each of said anodes, and means for applying a negative potential to said tubular member.

li. An apparatus for electrodepositing metal simultaneously on the inner and outer surfaces of a bearing shell comprising a container for an electroplating solution, means for supporting a bearing shell in said container, a pumping unit for moving said solution in said container to said support means, an electroplating solution flow-directing tube communicating said pumping unit with said support means, means for supporting an insoluble cylindrical anode within said bearing shell in spaced relationship so as to form an annular inner chamber therebetween, means for circumferentially surrounding said bearing shell with a tubular second anode which is spaced therefrom so as to form an outer annular chamber therebetween, said support having apertures therein communicating said directing tube with said chambers for simultaneously directing said electroplating solution into said inner and outer chambers, said inner cylindrical anode having a conical tip on its lower end which coacts with an aperture in said support so as to regulate the rates of flow of said solution through said chambers, means for applying a separately variable positive potential to each of said anodes, and means for applying a negative potential to said bearing shell.

12. An apparatus for electrodepositing metal simultaneously on the inner and outer surfaces of a tubular lmember comprising a container for an electroplating solution, means for supporting a tubular member in said container, a pumping unit associated with said container, an electroplating solution how-directing tube communicating said pumping unit with said support means, means for supporting an insoluble cylindrical anode within said tubular member in spaced relationship so as to form an annular inner chamber therebetween, means for circumferentially surrounding said bearing shell with a tubular second anode which is spaced therefrom so as to form an outer annular chamber therebetween, said support having apertures therein communicating said directing tube with said chambers for simultaneously directing said electroplating solution into said inner and outer chambers, said inner cylindrical anode having a conical tip on its lower end which coacts with an aperture in said support so as to regulate the rates of flow of solution through said chambers, means for applying a separately variable positive potential to each of said anodes, and means for applying a negative potential to said tubular member.

13. An apparatus for electrodepositing metal simultaneously on the inner and outer surfaces of a bearing shell comprising a reservoir for containing an electronlating solution, means for supporting a bearing shell with its longitudinal axis in vertical disposition, a pumping unit for moving an electroplating solution from said reservoir to said bearing shell, an electroplating solution ow-directing tube communicating said pumping unit with said support, an electrically non-conductive masking ring for each end of said bearing shell, an annular groove in each of said masking rings into which said bearing shell is closely tted, an apertured end platefor retaining each ofsaid masking rings, means for supporting a cylindrical insoluble anode concentrically within said bearing shell between said end plates, said anode being spaced from said bearing shell so as to orm an annular chamber therebetween, a central tie bolt within said bearing shell vfor locating said anode and securing said end plates to said bearing shell, a conical member secured to the lower of said end plates, means for circumferentially surrounding said `bearing shell with an insoluble tubular second anode which is spaced theretrom so as to form an outer annular chamber therebetween, said bearing shell support having apertures therein communicating said directing tube With said chambers for simultaneously passing said electroplating solution into said inner and outer chambers, said conical member coacting with an aperture in said support so as to regulate the relative rates of flow of said solution through said chambers, means lfor applying a separately variable positive potential to each of said anodes, and means for applying a negative potential to said bearing shell.

14. An apparatus for electrodepositing metal simultaneously on the inner and outer surfaces of a bearing shell comprising a container for a silver electroplating solution, means for supporting a bearing shell in said container, said bearing shell having its longitudinal aXis in Vertical disposition, a pumping unit Vfor moving an electroplating solution from said container to said bearing shell, an electroplating solution flow-directing tube communicating said pumping unit with said support, an electrically non-conductive masking ring `for each end of said bearing shell, an annular groove in each of said masking rings into which said bearing shell is closely tted, an apertured end plate for retaining each of said masking rings, means for supporting a cylindrical insoluble anode concentrically within said bearing shell between said end plates, said anode being spaced `from said bearing shell so as to form an annular chamber therebetween, a central tie bolt within said bearing shell for locating said anode and securing said end plates, a conical member secured to the lower end of said bearing shell, means for circumerentially surrounding said vertically disposed bearing shell with an insoluble tubular second anode which is spaced therefrom so as to form an outer annular chamber therebetween, said bearing shell support having apertures therein communicating said directing tube with said chamt bers for simultaneously passing said electroplating solution into said inner and outer chambers, said conical member coacting with an aperture in said support so as to regulate the relative rates of flow of said solution through said chambers, means for applying a separately variable positive potential to each of said anodes, and means for applying a negative potential to said bearing shell.

15. A11 apparatus for electrodepositing metal simultaneously on the inner and outer surfaces of a bearing shell comprising a container for a silver electroplating solution, means for supporting a bearing shell in said container, said bearing shell having its longitudinal axis vertically disposed, a pumping unit associated with said container for providing movement of an electroplating solution from said container to said bearing shell, an electroplating solution how-directing tube communicating said pumping unit with said support, a split ring for circumferential engagement with the upper end of said bearing shell, insulating means interjacent said split ring and said bearing shell, an inner anode support member secured to said split ring extending over the upper end of said bearing shell, a cylindrical insoluble anode suspended from said anode support member within said bearing shell and spaced therefrom so as to form an annular chamber therebetween, said anode having a lower end which has a conical tip thereon, said anode and said shell forming a composite unit, means for circumferentially surrounding said bearing shell with an insoluble tubular second anode which is spaced therefrom so as to form an outer annular chamber therebetween, said bearing shell support having apertures therein communicating said directing tube with said chambers for simultaneously passing said electroplating solution into said inner and outer chambers, said conical tip of said inner anode coacting with an aperture in said support so as to regulate the relative rates of flow of said solution through said charnbers, means for applying a separately variable positive potential to each of said anodes, and means yfor applying a negative potential to said bearing shell.

16. An apparatus for electrodepositing a metal simultaneously on the inner and outer surfaces of a bearing shell comprising a reservoir for an electroplating solution, means for supporting a 'bearing shell with its longitudinal axis in vertical disposition, means `for moving an electroplating solution from said reservoir to said support, a split ring for circumferential engagement with the upper end of said bearing shell, means for insulating said bearing shell from said split ring, an inner anode support member secured to said split ring extending over the upper end of said bearing shell, the cylindrical insoluble anode suspended from said anode supported within said bearing shell, said anode and said bearing shell being spaced so as to form an annular chamber therebetween, said anode having a lower end which has a conical tip thereon, said anode and said shell lforming a composite unit, means for circumferentially surrounding said bearing shell with an insoluble tubular second anode which is spaced vtherefrom so as to form an annular chamber therebetween, said bearing shell support having apertures therein communicatingsaid directing tube with said chambers Ifor simultaneously passing said electroplating solution into said inner and outer chambers, said conical tip of said inner anode coacting with an aperture in said support so as to regulate the relative rates of ow of said solution through said chambers, means for applying a separately variable positive potential to each of said anodes, and means for applying a negative potential to said bearing shell.

References Cited in the tile of this patent UNITED STATES PATENTS 902,892 Lutz Nov. 3, 1908 1,526,644 Pinney Feb. 17, 1925 1,759,171 Soderberg et al May 20, 1930 1,772,074 Engelhardt et al Aug. 5, 1930 1,886,218 Olin et al. Nov. 1, 1932 2,014,566 Haskell Sept. 17, 1935 2,406,956 Matthews Sept. 3, 1946 2,431,949 Martz Dec. 2, 1947 

1. THE METHOD OF SIMULTANEOUSLY ELECTROPLATING THE INNER AND OUTER SURFACES OF A TUBULAR MEMBER, SAID METHOD COMPRISING THE STEPS OF GENERALLY CONCENTRICALLY DISPOSING IN SPACED RELATIONSHIP A FIRST CYLINDRICAL ANODE WITHIN SAID TUBULAR MEMBER, GENERALLY CONCENTRICALLY DISPOSING IN SPACED RELATIONSHIP A SECOND CYLINDRICAL ANODE AROUND THE OUTER SURFACE OF SAID TUBULAR MEMBER, CONCURRENTLY FLOWING AT MUTUALLY DIFFERENT RATES A STREAM OF ELECTROLYTE BETWEEN THE TUBULAR MEMBER AND EACH OF SAID ANODES, INDUCING A NEGATIVE POTENTIAL ON SAID TUBULAR MEMBER AND WHILE FLOWING SAID ELECTROLYTE INDUCING MUTUALLY DIFFERENT POSITIVE POTENTIALS ON SAID FIRST ANODE AND SAID SECOND ANODE SO AS TO ELECTRODEPOSIT IN A PREDETERMINED THICKNESS RATIO A METAL COATING ON EACH OF SAID SURFACES.
 3. AN APPARATUS FOR ELECTRODEPOSITING METAL SIMULTANEOUSLY ON THE INNER AND OUTER SURFACES OF A BEARING SHELL COMPRISING A SUSPPORT FOR A BEARING SHELL, MEANS FOR SUPPORTING A CYLINDRICAL ANODE WITHIN SAID BEARING SHEEL IN SPACED RELATIONSHIP SO AS TO FORM AN ANNULAR INNER CHAMBER THEREBETWEEN, MEANS FOR CIRCUMFERENTIALLY SURROUNDING SAID BEARING SHELL WITH A SECOND ANODE WHICH IS SPACED THEREFROM SO AS TO FORM AN OUTER ANNULAR CHAMBER THEREBETWEEN, MEANS FOR PASSING AN ELECTROPLATING SOLUTION SIMULTANEOUSLY THROUGH SAID INNER AND OUTER CHAMBERS, MEANS FOR REGULATING THE RELATIVE RATES OF FLOW OF SAID SOLUTION THROUGH SAID CHAMBERS, MEANS FOR APPLYING A POSITIVE POTENTIAL TO SAID ANODES, AND MEANS FOR APPLYING A NEGATIVE POTENTIAL TO SAID BEARING SHELL. 